1. Field of the Invention
The present invention relates to a device for aiding installation of suspended ceilings. More particularly, the invention is directed to a tool for use during ceiling grid installation which offers a faster and more accurate means of aligning cross-tee and main-tee ends into wall angle.
2. Related Art
As previously described and understood, the most common technique of installing a suspended acoustical ceiling, whether installed in a commercial building, or in a residential basement, is to suspend the ceiling grid under the joist supports with providing accessibility to mechanical equipment, plumbing electric, etc. These grids are typically installed level and at 90° angles to perimeter walls/partitions, but occasionally for building constraints or aesthetics are installed at acute angles, for example, such ceilings as a cathedral, sloped, diagonal, or free floating unattached to perimeter walls (to accent a small section of a large room such as over a grocery kiosk).
In a typical suspension ceiling grid using 2×4 foot ceiling tiles, so-called “main-tees” are portions of the grid spaced on four foot centers and “four foot cross-tees” are spaced on two foot centers. The main-tees and cross-tees are intended to be interlocked in straight lines at 90° angles to create a 2×4 foot rectangular grid to receive and hold finish components such as ceiling tile, lights, hvac diffusers, etc. Other grids require 2×2 foot tile, etc., and in such case two foot cross-tees are perpendicularly interlocked in center slots of the four foot cross-tees. The main-tees are suspended by hanger wires looped through provided holes in main-tee together with the wall angle which is secured to the wall, which together support the cross-tees and all other finish components.
Typically, the sequence of installation begins with establishing a grid lay-out and a finish elevation. Lay-out determines the direction of the main-tees and cross-tees taking into consideration such things as desired location of lights, hvac diffusers, etc. Elevation is often determined by height of plumbing pipes, ductwork etc. above.
Commercially, architectural drawings are usually supplied and the room need only be measured to mark locations of main-tees and cross-tees and to verify that prescribed elevation will provide clearance of all other work above. Once lay-out is completed, hanger wires are installed on four foot centers in line with main-tees by attaching to structural members above such as joists, beams, or decking etc. and wall angle is fastened to perimeter walls/partitions. Laser levels (or optionally water levels, strings, and chalk lines) are commonly used for leveling of wall angle and main-tees.
A corner of the room is usually designated as a starting point. Two perpendicular string lines are stretched along the two adjacent walls, one in position of the first main-tee, and the other at a 90° angle in line with the first row of cross-tees. One end of the first row of main-tees is trimmed such that when a cut end is placed in the wall angle, a tee slot is on the first cross-tee line. Cross-tees are cut to measurement of inside wall angle to the main string line such that when interlocked to the main-tee with the cut end in wall angle, the first main-tee is in position on the first main string line.
The first main-tee is trimmed accordingly and suspended level by hanger wires with cut end temporarily clamped to wall angle to position properly on both the main string line and a tee slot on the cross-tee string line. Then starting at the slot on the first cross-tee string line and continuing every two foot, cross-tees are cut and interlocked to main-tee with cut edge temporarily clamped to wall angle so as main lines up on first main border line. A second main is then trimmed and suspended in the same manner temporarily clamped in place to the wall angle with a tee slot on the cross-tee line. Four foot cross-tees are interlocked in established cross-tee slots between the two mains.
Both diagonal measurements of a full space are then checked to see if the grid is square (a term used in the industry for 90° angles applied to rectangles, as well as squares). If out of square, the grid must be shifted off one line or the other until square. If shifted, string lines are then adjusted to the grid's new location.
Main-tees are then again checked for level to laser light, and hanger wires are tied off at main-tees. Cross-tee and main-tee ends must then be squared/aligned into permanent position and riveted to wall angle. This process is typically done by sighting for straight as locations of cross-tees cannot simply be measured and marked on wall mold as grid systems are of nominal size and spacing is not in equal full inch increments, therefore calculations must be made to measure. This is time consuming yet performed in the art. Some use a string line to be tied to a clip on opposite sides of a room, and then move the clips down the walls. With regard to squaring main-tee and cross-tee ends, it is impracticable as it would require installer to travel back and forth from one side of the room to the other to move lines, and if the room doesn't have straight walls, the strings knots must continually be retied, these procedures take too much time. This procedure in reference to leveling grid is no longer preferred with the advent of construction lasers. The remainder of the grid is filled in from each string line away to an opposite wall. Subsequent to installation of lights, hvac equip, etc. and inspections, ceiling tile is installed by first cutting borders to fit smaller non uniform grid areas, and then laying in the full tile.
There thus remains a need to improve the method and device for installing suspended ceilings.